Kingfisher family ‘busy blue sparks’ seen daily on French stream
One of the consequences of this summer’s rainfall deficit was the reduction in the flow of the tributaries of the main rivers, in our case the Aude.
We live in a watermill perched above the Brézilhou stream (stream), and not for the first time see why the original mill, dating back around 900 years, was built here.
Upstream, all the flow passed underground, but if the waterfall that feeds the mill pond slowed down, it would still have provided enough to turn the heavy wheels.
Electric blue spark of a kingfisher
Somewhere upstream, a pair of kingfishers (Kingfisher) nest each year.
I have not found the current nest, the oldest from previous years were washed away by the floods which will eventually return.
This year we saw a kingfisher almost every day; there’s often a spark of electric blue and a screeching sound as this year’s family treks a mile to the main river to hunt for food – and sometimes they stop at the pond and try their luck here .
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The Kingfisher family stand up for the water together
So, a few days ago, I was delighted to see three of them taking flight simultaneously from different perches around the pond.
They would have been from the same family; a kingfisher – male and female – will hold and defend a sufficient length of water for their needs, and they may merge their territories in February if they choose to breed together.
If successful, the six to seven eggs laid in March or early April will hatch at the end of the tunnel of the nest built in a sandbar where a chamber is dug.
They fledge in about twenty-five days, are fed for another four days, and then the parent pair will drive them away – so fast that some of them have not yet learned to fish on their own, and therefore die – and then continue to have one or even two more broods in the same year.
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Fair Feeding Routine in the Nesting Chamber
The researchers saw that there is a wonderful feeding device in the nest chamber, where the chicks spin around in a sort of star formation waiting for the next parent to return with their beak full of fish.
If it works, each chick gets a turn, then they all mix!
Whether it’s as perfect as that is another question, but ideally that’s how it works.
Kingfisher numbers fluctuate wildly from year to year
A severe winter will decimate numbers, but with breeding success they may rebound.
More importantly, by mid-September each bird will have had to establish its own winter territory, in order to provide enough food for the difficult months ahead.
Only a quarter of the adults survive from one season to the next and very few reproduce more than one season.
All of this shows that species live in the fast lane.
Each adult must eat at least its body weight in small fish, or prawns and tadpoles each day, and in the nest each gaping mouth will eat six or seven minnows a day.
A busy life, and often ended very quickly.
Kingfisher staring at its prey; Photo: Adrian Henderson
Note the intense gaze in the photo above; after fixing a prey and judging its depth, it will dive, opening its beak and closing the protective lid, effectively diving blind – but it works!
Why are kingfishers bright blue?
Needless to say, the most striking thing about kingfishers that we humans notice is their brilliant colors.
So the question this raises is why evolution has developed something so extraordinarily dazzling. Interestingly, most of my pictures only show male kingfishers, the females have a red base on the lower beak – they’re “wearing lipstick”, the joke goes.
However, my friend Adrian has a photo that shows a hint of red at the base of the beak, so a female, but probably a juvenile.
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Since the time of Darwin, it has been known, and proven by modern research, that it is very often females who do the sexual selection of mates on criteria that we humans are just too slow and inattentive to see. , unless we use photography. and scientifically studying colors (and sounds and movements).
Many birds also see in the UV spectrum, and therefore a color will have a range of subtlety beyond our capabilities.
All of these clues can give a discerning female information about a male bird’s health and vigor, and she’ll choose whether to mate with him – or not – based on what she’s able to detect, sometimes in a flash. , as he patrols a neighbor’s house. territory.
So a bright blue and bright orange chest can cause it to choose a mate and pass those characteristics on to its offspring, and so evolution works its magic.
Broad-tailed Hummingbird good example of speed in courtship
An example of the rapidity of existence in the avian world is shown by a bird which none of us will see unless we travel to America; the broad-tailed hummingbird.
It has a demonstration flight which is “one of the coolest and weirdest courtship shows in the world” according to Mary Caswell Stoddard who studied them in Colorado.
The details are intricate and wonderful, but just know that the male dives on a perched female at a speed of 385 times his body length per second, nearly double the speed of a diving peregrine (Peregrine Falcon), or the space shuttle during atmospheric re-entry (207 body lengths per second); at full speed at the bottom of his plunge his gorget [patch of colored feathers found on the throat] flashes a bright, sexy magenta, then its iridescent nature causes a change – in just 120 milliseconds – from bright red to dark green, as it passes overhead”.
The amazing thing is that the female can see these precise details, judge her vigor by the speed and luster of her plumage, and make a choice of partner accordingly…
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